Seal arrangement for pump motor leads

ABSTRACT

A secondary seal for submersible pump housings and comprising a resilient disc having a taper at its perimeter and plural tapered lead passing apertures adapted to snugly locally confine the motor leads and to maintain the resulting seal by perimetrical confinement and radial inward compression of the disc.

United States Patent [1 1 OBrien [4 1 Nov. 13, 1973 SEAL; ARRANGEMENTFOR PUMP MOTOR LEADS Inventor: Terrance J. OBrien, Anaheim,

Calif.

Assignee: Purex Corporation, Ltd., Lakewood,

Calif.

Filed: June 15, 1972 Appl. No.: 262,947

US. Cl. 174/65 SS, 310/71, 310/87 Int. Cl. H02k 5/10 Field of Search174/65 R,- 65 SS,

References Cited UNITED STATES PATENTS l0/l940 Hawley 310/87 9/1962Peterson 174/65 SS FOREIGN PATENTS OR APPLICATIONS 65,307 10/1942 Norway174/65 SS OTHER PUBLICATIONS J. C. Lyons, IBM Technical DisclosureBulletin, Vol. 1, No.5, Feb. 1959, page 35.

Primary Examiner-Bernard A. Gilheany Assistant ExaminerD. A. ToneAttorney-Louis J. Bachand, Jr. et al.

[57] ABSTRACT A secondary seal for submersible pump housings andcomprising a resilient disc having a taper at its perimeter and pluraltapered lead passing apertures adapted to snugly locally confine themotor leads and to main- 7 tain the resulting sea] by perimetricalconfinement and radialinward compression of the disc.

7 Claims, 4 Drawing Figures SEAL ARRANGEMENT FOR PUMP MOTOR LEADSBACKGROUND OF THE INVENTION This invention has to do with improvementsin the sealing of submersible housings for electrical devices againstincursion of water or other fluid likely to corrode or destroy motor andother device components. More particularly, the invention is concernedwith a novel seal arrangement for motor leads to a junction box wherepower cable leads are connected to motor leads.

PRIOR ART It is known to fluid tightly secure power cable to a junctionbox for a submersible pump housing by supporting a cable grip assemblyby means of an adapter bushing threaded into a wall opening of thejunction box. This connection is normally fluid tight. Within thejunction box the power cable leads, including a ground lead are suitableconnected, e.g., the ground lead to the junction box wall which can beintegrally formed with the pump discharge case or other metal housing,and the power leads to the motor leads as desired. The motor leads aretypically three to nine in number and correspond to power cable leads.These leads are joined by connectors known per se.

The motor leads pass into the junction box from the motor chamber of thepump housing through an opening provided. It is with the effectivesealing of this opening that the present invention is concerned. In theabsence of effective sealing at this location, any failure, eithercatastrophic or by seepage of fluid through and around the primary cablegrip seal will permit incursion of fluid e.g., water, or corrosive gasesinto the motor proper, necessitating motor replacement or extendedrepair, rather than the much less costly seal repair.

SUMMARY OF THE INVENTION Accordingly, it is an object of the presentinvention to provide a means to overcome the problem of relatively greatdamage to motor and other parts which may be occasioned byfailureof'theprimarycable seal in a submersible pump or like'apparatus.

Specifically, the invention provides, in a submersible housing for apump motor or the like, which includes a first wall opening throughwhich motor leads extend and a second wall opening at which a powercable is secured normally against fluid entry, the power cable leadsbeing connected to the motor leads, the improvement comprising sealmeans for said first opening against fluid seepage from the junction boxto the motor in the event of leakage failure at the second wall opening,the seal means comprising a resilient wafer or disc having pluraltapered apertures extending axially thereof, the aperture walls havinglocal radial deflectability outward in response to insertion of anindividual motor lead to effect a seal around such lead, the disc orwafer having an axially longitudinally tapered perimeter relativelylarger at its greatest diameter than said first opening for insertioninto said first opening in perimetrically compressed relation to limitoutward deflection of said aperture walls to maintain a seal at saidfirst opening. The disc is typically formed on an elastomeric material,e.g., such material having a Durometer value of at least 30 Shore A andpreferably 50 to 60 Shore A.

The apertures may be equidistantly and preferably uniformly circularlydistributed, e.g., about a central aperture and in diametrically opposedpairs. The apertures typically have a common degree and direction oftaper, the perimeter taper also being common in direction with theaperture taper. The degree of perimeter taper generally is approximatelythe same orrelatively greater than the degree of aperture taper, e.g.,0.5 to times as great.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will be furtherdescribed in conjunction with the attached drawings in which FIG. 1 is aview of elevation of a submersible pump, to which the present inventionis typically applied;

FIG. 2 is a detail view in vertical section of the junction box portionof the pump, the view being taken on line 22'in FIG. 1;

FIG. 3 is a center vertical section of the seal disc of the invention,in position; and

FIG. 4 is a front view of the disc, taken on line 4-4 in FIG.3.

DESCRIPTION OF THE PREFERRED EMBODIMENTS With reference now to thedrawings, the seal arrangement of the present invention is particularlyadapted to submersible pumps such as that shownat l in FIG. 1. Pump 1comprises a housing 2, having an inlet at 3 surrounded by screen 4, anda discharge case 5 having an outlet at 6. Power cable 7 is connectedinto the discharge case at 8. j a

In FIG. 2,- junction box 9 formed within the discharge case 5 is shownhaving a wall opening at 10 into which adapter 11 is inserted, butted atshoulder 12 to the case wall 13 and secured, sealed by O-rings 14against fluid entry from without the pump, at 15. The cable 7 is securedto the adapter 11 by cable grip 16 threaded onto the adapter overbushing 17.

The junction box 9 has another wall opening 18 which communicates thejunction box interior 19 with the motor chamber 20. The invention isconcerned with sealing the opening 18. V I,

As will be apparent from the drawings, the several power cable leads 21,22, 23, representative of any number of such leads, e.g., three to ninemotor leads, extend through opening18 from the motor chamber 20 to thejunction box interior 19. The cable 7 is grounded by lead 24 connectedby screw 25 to the discharge case 5. Other power cable leads 26, 27 areconnected to motor leads 23, 22 by means of conventional connectors 28,

Aswill be evident, the junction box 9 and the leads and connectionstherewithin are primarily protected from water, moisture vapor or otherharmful fluid, e.g., corrosive gases in which the pump might be placedby the O-ring seals 14 about the adapter 11.

This invention provides a secondary seal between the motor chamber 20and junction box 9 in the event of failure at the primary seal point. Inthis manner, if the primary seal fails, and, e.g., water enters thejunction box 9, the device is at most shorted out; but the motor, andother components beyond the junction box are protected. Moreover, thejunction box connections may be potted to prevent even shorting out.Accordingly repair of the pump will involve merely replacement of theO-ring seals 14.

The mentioned secondary seal is best shown in FIG. 3 and comprises acircular disc 30 which is fitted into an annular groove 31 formed in thejunction box wall opening l8. The disc is formed of an elastomericmaterial, such as. natural or synthetic rubber, ethylenepolymeric, e.g.polyolefin material having sufficient resilience, i.e., an ability torecover its shape when distorted. Suitable as such materials are thosehaving a Durometer number above about 30 Shore A. The disc 30 is formedwith a tapered perimeter 32 for purposes to appear.

A plurality of lead passing apertures 33 are provided in the disc 30. Atypical arrangement is shown in FIG. 4 where a central aperture 33a isshown with radially displaced apertures 33b-i distributed circularlytherearound and in diametrically opposed pairs, e.g., 33h and 33d. Otherarrangements may be used and the number and spacing of apertures 33a-ivaried to correspond to the number of motor leads.

The disc apertures 33a-i are each commonly tapered along thelongitudinal axis of the disc 30 to a minimum diameter at 34 which isless than the average diameter of the motor lead 21-23 whereby theaperture receiving the lead is locally deflected as at 35 to accommodatethe greater lead diameter. The resilient nature of the disc 30 as notedabove gives a local deflectability to the aperture walls 36 enabling thestretching accommodation of the inserted lead. The relatively widerportion of the apertures 33a-i facilitates locating the lead in anaperture. The degree of taper in each aperture is typically between 2and 5 and both the .degree of taper and direction of taper are generallycommon among the several apertures.

As noted, the perimeter 32 of the disc 30 is likewise tapered. Themaximum diameter of the disc is greater than the diameter of annulargroove 31 defining the junction box wall opening 18. Accordinglyinsertion of the disc 30 into the groove 31 circumferentially compressesthe disc exerting a squeezing or restrictive zone on the apertures 33a-iwhich limits or restricts the local deflection of the aperture walls 36and accordingly en- ;hances the snugness of fit of the disc 30 into thegroove 31, all to ensuring a leak-proof closure across the wall opening18.

I claim;

1. In combination: a submersible housing for a pump motor or the like,which includes a first wall opening through which motor leads extend anda second wall opening at which a power cable is secured normally againstfluid entry, said power cable having leads connected to the motor leads,and seal means for said first opening against fluid seepage to the motorin the event of leakage failure at the second wall opening, said sealmeans comprising a resilient disc having plural tapered aperturesextending axially of the water disc, the aperture walls having limitedlocal radial deflectability outward in response to insertion of anindividual motor lead to efiect a seal around such lead, said dischaving a longitudinally tapered perimeter relatively larger at itslargest dimension than said first opening for insertion into said firstopening in perimetrically compressed relation to restrict outwarddeflection of said aperture walls to maintain a seal at said firstopening.

2. The combination according to claim 1 in which said disc perimetertaper is from 0.5 to 5 times greater than said aperture taper.

3. The combination according to claim 1 in which said disc is formed ofelastomeric material.

4. The combination according to claim 1 in which said disc apertures areequidistantly distributed.

5. The combination according to claim 1 in which said apertures having acommon degree and direction of taper and said perimeter taper is commonin direction with said aperture taper.

6. The combination seal means according to claim 1 in which'said discapertures are uniformly circularly distributed.

7. The combination according to claim 6 in which said disc is formed ofan elastomeric material having a Durometer value of at least 30 Shore A.

1. In combination: a submersible housing for a pump motor or the like,which includes a first wall opening through which motor leads extend anda second wall opening at which a power cable is secured normally againstfluid entry, said power cable having leads connected to the motor leads,and seal means for said first opening against fluid seepage to the motorin the event of leakage failure at the second wall opening, said sealmeans comprising a resilient disc having plural tapered aperturesextending axially of the water disc, the aperture walls having limitedlocal radial deflectability outward in response to insertion of anindividual motor lead to effect a seal around such lead, said dischaving a longitudinally tapered perimeter relatively larger at itslargest dimension than said first opening for insertion into said firstopening in perimetrically compressed relation to restrict outwarddeflection of said aperture walls to maintain a seal at said firstopening.
 2. The combination according to claim 1 in which said discperimeter taper is from 0.5 to 5 times greater than said aperture taper.3. The combination according to claim 1 in which said disc is formed ofelastomeric material.
 4. The combination according to claim 1 in whichsaid disc apertures are equidistantly distributed.
 5. The combinationaccording to claim 1 in which said apertures having a common degree anddirection of taper and said perimeter taper is common in direction withsaid aperture taper.
 6. The combination seal means according to claim 1in which said disc apertures are uniformly circularly distributed. 7.The combination according to claim 6 in which said disc is formed of anelastomeric material having a Durometer value of at least 30 Shore A.